In many geographical areas, daytime temperatures during summer periods rise to levels which are uncomfortable for many outdoor work or recreational activities, such as construction work, oil and gas well operation, lawn and garden care, and outdoor sports activities. People who engage in outdoor work or recreational activities on hot sunny days usually have little relief from the heat, other than an occasional breeze or cloud cover.
Although refrigerated air conditioning has found widespread usage in many parts of the world, it is, of course, completely impractical for cooling outdoor areas. In addition, there remain many types and uses of buildings for which refrigerated air conditioning is unavailable, impractical or cost prohibitive. Examples of buildings and uses in which air conditioning is normally not provided include vehicle repair garages, gymnasiums, warehouses, welding shops, sheet metal fabrication shops and aircraft hangars. During hot summer periods, these non-air conditioned buildings can become very warm and uncomfortable for their occupants. Although electric fans are frequently used in an attempt to make non-air conditioned spaces more comfortable, fans only circulate the warm air without reducing the temperatures and, therefore, have limited success in improving comfort.
Some non-air conditioned buildings are equipped with an evaporative cooling system which moves warm air through air-permeable, water saturated pads to lower the air temperature by moisture evaporation. This system utilizes an evaporative cooling unit which is usually roof-mounted and contains an electric motor-driven blower, a water pump and the air-permeable pads. Water is provided to the evaporative cooling unit through piping connected to the building plumbing system.
The primary advantage of evaporative cooling over refrigerated air conditioning is its much lower operating cost. However, permanent positive pressure evaporative cooling systems are best suited for building spaces having low ceilings for providing air distribution outlets. Evaporative cooling systems are usually not feasible for large building spaces having high ceilings, such as gymnasiums, aircraft hangars and many warehouses. In buildings for which it is feasible, a permanent positive pressure evaporative cooling system usually requires, in addition to the evaporative cooling unit themselves, custom fabrication and installation of a ducted air distribution system similar to that required for a refrigerated air conditioning system. In fact, a positive pressure evaporative cooling system usually requires larger air supply ducts than a refrigerated air conditioning system because of the high air flow rates required. Therefore, a permanent positive pressure evaporative cooling system can be nearly as expensive to install as refrigerated air conditioning, and its expense is frequently too high to be justified. This is particularly true for buildings which are infrequently occupied by people, such as warehouses, greenhouses and aircraft hangars.
Consequently, a need exists for an apparatus for providing air cooling in buildings for which refrigerated air conditioning and permanent evaporative cooling systems are unavailable, impractical or cost prohibitive. Preferably, such a cooling system will be self-contained, compact and easily portable, so that it can be moved about from place to place to provide cooling where temporarily needed. Such cooling apparatus will preferably also be inexpensive and simple to manufacture, have a low operating cost and be operable on standard 110 volt electric current. Ideally, such cooling apparatus will be usable either indoors or outdoors.
As part of these apparatus, a spray bar assembly is provided which sprays the water upwardly onto a bonnet, such that it may then fall down against the water absorption media. Even though jets of water are forced through the pipe and the jets of water impinge on the inner surface of the bonnet, the water is not fully dispersed and some dry spots are left. Impingement alone does not distribute the circulated water evenly to the evaporative medium. Evaporative cooler recirculation pumps do not produce high enough head pressure to allow impingement spreading alone to function well. Also, spraying the water up against the bonnet causes water to come into contact with the housing itself. The water does not drop away from the bonnet, but follows the bonnet to the outer sides of the water absorption media, thereby not fully saturating the water absorbing media. This can cause leaks, corrosion and other problems. Also, the water can be sprayed around the area as it deflects off of the bonnet.